Method of Reinforcing a Hollow Part Which Is Formed in an Earth and Sand Ground at a Rear Side of Retaining Wall

ABSTRACT

A method of reinforcing a hollow part which is formed in an earth and sand ground at a rear side of retaining wall by a revetment work is disclosed. The method of reinforcing a hollow part which is formed in an earth and sand ground at a rear side of retaining wall by a revetment work, the method including: forming a base hole by excavating the earth and sand ground facing to a base bottom surface of the retaining wall by a predetermined depth; forming a support wall by foaming first hard urethane at an inlet of the hollow part formed by the base bottom surface of the retaining wall and lost earth and sand and forming a underwater wall by foaming second hard urethane between the base hole, the support wall, and the base bottom surface of the retaining wall; forming a reinforcing layer by foaming third hard urethane at a upper part of a bottom surface of the hollow part, a upper part of the support wall, and a upper part of a bottom plate of the retaining wall; forming a urethane and crushed stone layer by using alternatively crushed stones and fourth hard urethane at a upper part of the reinforcing layer; and forming an impact relieving layer by using fifth hard urethane between a road formed at a upper part of the hollow part and the urethane and crushed stone layer. Therefore, it is possible to semi-permanently reinforce a hollow part which is formed in an earth and sand ground at a rear side of retaining wall within a short work period.

TECHNICAL FIELD

The present invention relates to a method of reinforcing a hollow part, and more particularly, to a method of reinforcing a hollow part which can repair and reinforce a hollow part which is formed in an earth and sand ground at a rear side of a retaining wall formed by a revetment work.

BACKGROUND ART

In general, a retaining wall that is a structure which is constructed by a revetment work for protecting an earth and sand ground adjacent to rivers or the sea should be provided to be oblique to endure to running water of rivers or waves and flood tide of the sea in view of a characteristic of a structure. However, in order to employ a small country area to the maximum, retaining walls constructed by many revetment works of our country are provided in a perpendicular direction in a portion in which earth and sand which come in contact with rivers or the sea meet, an earth and sand ground is stacked by a height of the retaining wall in a rear side of the retaining wall, and a road, etc. is provided thereon.

The retaining wall provided in the perpendicular direction continuously receives an impact of running water of rivers or waves of the sea and flood tide. As time flows, seawater, etc. percolates between a base bottom surface of the retaining wall and an earth and sand ground coming in contact with the base bottom surface. Accordingly, a channel type hollow part for incoming and outgoing of seawater, etc. is provided at a portion having low coupling strength among a coupling part of the base bottom surface of the retaining wall and the earth and sand ground. Further, if long time flows after the retaining wall is constructed, the channel type hollow part is gradually increased due to continuous erosion of the earth and sand ground and a large hollow part is formed as a large amount of earth and sand is discharged to rivers or the sea. Such a large hollow part causes depression or damage of a road surface formed in the rear side of the retaining wall, whereby traffic accident or obstacle can be induced and the retaining wall itself may collapse, so that an inclined retaining wall should be newly provided.

In order to remove an existent retaining wall provided in a perpendicular direction and reconstruct a new concrete inclined retaining wall, earth and sand ground positioned in the rear side of the retaining wall should be destroyed and a road, a rice paddy, a field, various residing construction, etc. which are formed on the existent earth and sand ground should be removed. Further, a long construction period is required for reconstruction, a time and a cost for installing an entire retaining wall are much consumed and cement solution which is outpoured from a newly installed concrete retaining wall contaminates rivers or the sea, so that a neighboring aquafarm is damaged. When a road to be removed is constructed on an earth and sand ground, neighboring residents feel inconvenience due to road block for construction.

Therefore, due to these problems, before newly constructing an inclined concrete retaining wall, it is preferable to perform a reinforcement work for reclaiming a large hollow part with a method of preserving an existent retaining wall and road in view of cost reduction.

Recently, if it is proved that a large hollow part exists in an earth and sand ground at a rear side of retaining wall, a reinforcement work for reclaiming a large hollow part is performed with a method of measuring a position, a size, and a shape of the hollow part with the naked eye, removing a paved road and earth and sand at the upper of the earth and sand ground by excavating from the ground, and then filling up new earth and sand in the large hollow part. However, a reinforcing method of excavating from the ground and filling up earth and sand should carry out a large amount of earth and sand and reclaim again the carried earth and sand, and requires a long time. Further, when a road is constructed on an earth and sand ground, traffic obstacle of long term is caused, the earth and sand charged through the existent large hollow part are outpoured to rivers or the sea and contamination of rivers or the sea due to this outflow damages a cultivating industry, etc., the large hollow part filled with earth and sand becomes again empty, and thus reconstruction may be required.

To solve the problem, conventionally, a method of boring a through hole with an equipment such as a hole cutter equipment up to the large hollow part and pouring concrete or mortar instead of earth and sand into the large hollow part through the through hole has been used.

However, in the method of pouring concrete or mortar, it is impossible to completely fill with concrete, etc. up to the top of the large hollow part, the construction is slowly performed due to long curing time, and it is difficult to cure concrete or mortar when much moisture exists in the large hollow part. Further, because the filled concrete or mortar has weak adhesive strength for the earth and sand ground forming the existent large hollow part or the existent concrete retaining wall, the earth and sand ground forming the existent large hollow part and earth and sand ground of the bottom which comes in contact with rivers, the sea is again eroded by seawater, etc., and thus the hollow part may be again formed. Therefore, a reinforcement work should be again performed. Furthermore, cement solution from filled concrete or mortar may be outpoured to rivers or the sea concrete to cause contamination.

DISCLOSURE Technical Problem

Accordingly, an object of the present invention is to solve at least the problems and disadvantages of the background art.

An object of the present invention is to provide a method of reinforcing a hollow part which can semi-permanently repair and reinforce a hollow part which is formed in an earth and sand ground at a rear side of retaining wall by a revetment work within short time.

Technical Solution

According to an aspect of the present invention, there is provided a method of reinforcing a hollow part which is formed in an earth and sand ground at a rear side of retaining wall by a revetment work, the method including: forming a base hole by excavating the earth and sand ground facing to a base bottom surface of the retaining wall by a predetermined depth; forming a support wall by foaming first hard urethane at an inlet of the hollow part formed by the base bottom surface of the retaining wall and a lost earth and sand and forming a underwater wall by foaming second hard urethane between the base hole, the support wall, and the base bottom surface of the retaining wall; forming a reinforcing layer by foaming third hard urethane at a upper part of a bottom surface of the hollow part, a upper part of the support wall, and a upper part of a bottom plate of the retaining wall; forming a urethane and crushed stone layer by using alternatively crushed stones and fourth hard urethane at a upper part of the reinforcing layer; and forming an impact relieving layer by using fifth hard urethane between a road formed at a upper part of the hollow part and the urethane and crushed stone layer.

The method may further include forming a coloring layer by coating urethane primer on an outside surface of the underwater wall; forming a urethane paint layer by coating urethane paint on the coloring layer; and forming a sand layer by coating sand on the urethane paint layer.

The reinforcing layer and the urethane and crushed stone layer may be formed in a V-shape and density of the first hard urethane may be 250 kg/m³, density of the second urethane may be 500 kg/m³, density of the third urethane may be 80 kg/m³ to 100 kg/m³, density of the fourth urethane may be 300 kg/m³, and density of the fifth urethane may be 60 kg/m³.

DESCRIPTION OF DRAWINGS

The invention will be described in detail with reference to the following drawings in which like numerals refer to like elements.

FIG. 1 is a flowchart illustrating an entire work of a method of reinforcing a hollow part according to the present invention; and

FIGS. 2 to 4 are views illustrating a method of reinforcing a hollow part according to an embodiment of the present invention.

BEST MODE

Hereinafter, exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

In a method of reinforcing a hollow part according to an embodiment of the present invention, a material which is mainly used for repairing a hollow part is polyurethane. Urethane is generated by chemical reaction of polyol and isocynate and polyurethane is made of many urethane units within a molecule. A property of polyurethane is decided by polyol and isocynate and a curing time thereof on the spot construction can be adjusted from several seconds to a desired time due to strong reactivity of polyol and isocynate, so that polyurethane has faster workability and curing ability, and longer airtight ability than any spot construction material. In the present invention, a method of reinforcing a hollow part by using several kinds of hard urethane having a different curing time and strength is used.

FIG. 1 is a flowchart illustrating an entire work of a method of reinforcing a hollow part according to an embodiment of the present invention and FIGS. 2 to 4 are views illustrating a method of reinforcing a hollow part according to an embodiment of the present invention. Referring to FIGS. 1 to 4, a method of reinforcing a hollow part according to an embodiment of the present invention will be described.

First, FIG. 2 shows a channel type hollow part formed on a junction surface of a retaining wall that is a concrete structure and a ground. The hollow part 1 is formed from an earth and sand ground 3 which comes in contact with the bottom surface of a revetment retaining wall 5 of rivers or the sea to a road 7 on the earth and sand ground 3 provided in the rear side of the retaining wall 5. In order to stably maintain upright in the earth and sand ground 3, a low plate 5 a of the retaining wall 5 protruded from a bottom side to a rear side is integrally formed, whereby the retaining wall 5 is entirely formed in a ‘+’ shape.

A reinforcing work of the hollow part 1 thus formed is performed with the following processes.

First, an exploration work and a confirmation work of an inside hollow part are performed (S100). The hollow part 1 can be confirmed its existence by an exploration work of a ground penetrating radar (GPR). The GPR exploration can grasp a form of a structure by providing a high resolution image for a structure with a nondestructive measurement method of using radar technology. Because the hollow part 1 is not found on a road 7 until the hollow part 1 develops, its existence can be confirmed with the GPR exploration work, etc. However, when deformation such as crack is generated on the road 7, the hollow part 1 often reaches justly below the road 7. Therefore, in this case, existence of the hollow part 1 can be confirmed by boring a hole in which a person can enter and inserting a fiberscope or a television camera, etc. at a presuming position of the hollow part 1 without performing underground structure exploration, etc. with supersonic wave or ultrahigh frequency of electric wave, etc.

If it is confirmed that the hollow part 1 exists, a shape or volume, etc. thereof is measured. A property, a state, a necessity amount, etc. of crushed stone and urethane to be foamed and charged within the hollow part 1 are calculated based on the measurement data and soil observation data, etc. around the hollow part 1 and urethane, crushed stone, and other necessary material and equipment are prepared (S100).

In a next step, a underwater wall 11 is formed (S120). This step is composed of the following processes. That is, an earth and sand ground facing to the base bottom surface of the retaining wall is dug by a depth of 500 to 1000 mm. In general, when the earth and sand ground is dug by a depth of 500 to 1000 mm, seashore base rock is exposed. As shown in FIG. 3, the underwater wall 11 can be integrally fixed to the seashore base rock.

When seashore base rock is not appeared even if an earth and sand ground facing to a base bottom surface of the retaining wall is dug in a depth of 500 or 1000 mm, stones having a diameter of approximately 100 to 1000 mm are filled into the dug hole 13. The support wall 11 b is provided by foaming with the first hard urethane (density: 250 kg/m³) a hollow part of the entrance which is formed by a low side of the bottom plate 5 a of the retaining wall and lost earth and sand and the support wall 11 b strongly supports the underwater wall 11 to be provided later.

Thereafter, the second hard urethane (density: 500 kg/m³) is foamed and injected into gaps formed in base rock or stones and the second hard urethane is foamed to a top level of the dug hole 13, so that a base 11 a of the underwater wall 11, which is integrally formed with base rock or stones, is constructed.

The base 11 a of the underwater wall 11 is integrally formed with base rock or the stones. Therefore, even if the earth and sand ground is eroded in the front of the base 11 a by waves or flood tide, etc., seawater, etc. can hardly percolate to the rear side of the existent retaining wall 7 because seawater, etc. exists in the bottom of the base 11 a. The underwater wall 11 is provided by stacking while foaming the second hard urethane until it comes in close contact with the bottom surface of the retaining wall in the same thickness as the existent retaining wall on the base 11 a. Therefore, the hollow part 1 is completely sealed from seawater, etc.

Because the base 11 a of the underwater wall 11 thus provided is integrally formed with the base rock or the stones and the upper part thereof is adhered to the bottom surface of the existent retaining wall 7 with high adhesive strength and the rear side thereof is supported by the support wall 11 b. Therefore, even if there is impact due to waves or flood tide, etc., seawater can not percolate between the existent retaining wall 5 and the upper part of the underwater wall 11 and river water or seawater can not percolate between the base 11 a of the underwater wall 11 and base rock or stones, so that the underwater wall 11 stably maintains upright in the earth and sand ground 3 a.

In a next step, a coloring process of an outside surface of the underwater wall 11 is performed (S130). At this step, a coloring agent layer 15 is formed by coating a primer for urethane that is a coloring agent by 1 to 2 mm on an entire surface of the underwater wall 11, a urethane paint layer 17 is formed by coating urethane paint corresponding to color of surrounding environment by 2 to 3 mm on the coloring agent layer 15, and the urethane paint layer 17 prevents a yellowing phenomenon of the underwater wall 11 by protecting the underwater wall made of a urethane quality weak in ultraviolet rays from ultraviolet rays. At this time, the primer induces strong adhesion of urethane and urethane paint.

Then, in order to remove traces of repair and protect the underwater wall 11 from indirect ultraviolet rays, a fine sand layer 19 for intercepting ultraviolet rays and harmonizing with surrounding environment is formed by coating fine sand by about 2 to 3 mm on a urethane paint layer 17 as soon as a coating work of urethane paint is completed.

In a next step, a reinforcement layer 21 in the bottom surface of the hollow part 11, etc. is formed (S140). To reinforce the poor earth and sand ground 3, a predetermined thickness of base layer 21 a is formed by foaming and coating the third hard urethane (density: 80 to 100 kg/m³) in a upper part of the earth and sand ground 3, a upper part of support wall 11 b, and a upper part of a bottom plate 5 a of the retaining wall except the earth and sand ground positioned within a distance of 300 to 400 mm from the earth's surface 7 a. When a rear side of the retaining wall is exposed, the third hard urethane is foamed and coated in the rear side thereof except the rear side of the retaining wall positioned within a distance of 300 to 400 mm from the earth's surface 7 a, whereby a protection wall 21 b of the retaining wall is formed in a predetermined thickness, so that the reinforcement layer 21 having entirely approximately a V-shape shape is formed.

When the base layer 21 a is formed, urethane forming the base layer 21 a is foamed, the foamed urethane is injected into gaps formed in the poor earth and sand ground 3, the bottom plate 5 a of the retaining wall, and the rear side of a lower end of the retaining wall 5 as a tree takes root in the ground, so that the poor earth and sand ground 3, the bottom plate 5 a of the retaining wall, and the lower end of the retaining wall 5 are reinforced. When the protection wall 21 b of the retaining wall is formed, urethane forming the protection wall 21 b of the retaining wall is foamed and the foamed urethane is injected into gaps formed in the weakened protection wall 21 b of the retaining wall as a tree takes root in the ground, so that the weakened protection wall 21 b of the retaining wall is reinforced.

In a next step, the urethane and crushed stone layer is formed (S150). That is, a V-shape crushed stone layer 23 a is formed by stacking crushed stones in a thickness of 200 to 300 mm on the V-shape reinforcement layer 21. The V-shape layer is repeatedly stacked until a top portion thereof has a distance of 300 to 400 mm from the earth's surface into space of the large hollow part formed due to lost soil by foaming the fourth hard urethane (density; 300 kg/m³) on the V-shape crushed stone layer 23 a to form a V-shape urethane layer 23 b in a thickness of 100 to 150 mm, whereby a V-shape reinforcement layer 21 and one body of urethane and crushed stone layer 23 are formed. The crushed stone layer 23 a and the urethane layer 23 b are formed in a V-shape to disperse an impact.

In a next step, an impact relieving layer 25 is formed. The impact relieving layer 25 is formed by foaming the fifth hard urethane (density: 60 kg/m³) in a space between the remaining road 7, the reinforcement layer 21, and the urethane and crushed stone layer 23, makes the reinforcement layer 21 and the urethane and crushed stone layer 23 to be one body, and prevents damage of the asphalt layer as well as absorbs an impact in which the asphalt layer coated on the road 7 can receive.

In a last step, processes of finishing the hole 9 formed on the road 7 with asphalt or cement, returning the road to an original state, and paving the road are performed. By these processes, the hollow part can be reinforced.

As described above, according to the present invention, it is possible to easily reinforce a poor earth and sand ground, a retaining wall, and a road and to easily repair a large hollow part while using an existent road and retaining wall as it is. Further, because the earth and sand ground coming in contact with the bottom surface of the retaining wall which is repaired and reinforced using urethane is not eroded, there is no risk that a large hollow part is generated, whereby a construction cost can be remarkably reduced and due to a short construction period, physical distribution transportation and traffic are not greatly affected. According to a construction method of the present invention, because the inside of a large hollow part is filled without a gap, strength of the ground including a reinforcement portion is fully increased. In addition, because a large scale of construction such as excavation of earth and sand through destruction of a paved road is not required, the number of processes is few and a construction period is short, so that after the construction ends, a road may be immediately used. Therefore, a period of time to impede traffic communication is decreased, there is little worry of environmental contamination due to the construction, and an entire construction cost can be reduced.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

INDUSTRIAL APPLICABILITY

According to a method of reinforcing a hollow part of the present invention, the method is used to repair and reinforce a hollow part which is formed in an earth and sand ground at a rear side of retaining wall by a revetment work. Therefore, it is possible to easily reinforce a poor earth and sand ground, a retaining wall, and a road and to easily repair a large hollow part while using an existent road and retaining wall just as it is. 

1. A method of reinforcing a hollow part which is formed in an earth and sand ground at a rear side of retaining wall by a revetment work, the method comprising: forming a base hole by excavating the earth and sand ground facing to a base bottom surface of the retaining wall by a predetermined depth; forming a support wall by foaming first hard urethane at an inlet of the hollow part formed by the base bottom surface of the retaining wall and lost earth and sand and forming a underwater wall by foaming second hard urethane between the base hole, the support wall, and the base bottom surface of the retaining wall; forming a reinforcing layer by foaming third hard urethane at a upper part of a bottom surface of the hollow part, a upper part of the support wall, and a upper part of a bottom plate of the retaining wall; forming a urethane and crushed stone layer by using alternatively crushed stones and fourth hard urethane at a upper part of the reinforcing layer; and forming an impact relieving layer by using fifth hard urethane between a road formed at the upper part of the hollow part and the urethane and crushed stone layer.
 2. The method of claim 1, further comprising forming a coloring layer by coating urethane primer on an outside surface of the underwater wall; forming a urethane paint layer by coating urethane paint on the coloring layer; and forming a sand layer by coating sand on the urethane paint layer.
 3. The method of claim 1, wherein the reinforcing layer and the urethane and crushed stone layer are formed in a V-shape.
 4. The method of claim 1, wherein density of the first hard urethane is 250 kg/m³, density of the second urethane is 500 kg/m³, density of the third urethane is 80 kg/m³ to 100 kg/m³, density of the fourth urethane is 300 kg/m³, and density of the fifth urethane is 60 kg/m³. 